1. Field of the Invention
The present invention is directed to improvements of a connector for and a method of connecting a resinous pipe having a relatively small diameter or a metallic tube having a diameter of approximately 30 m/m or less, which is arranged as a supply passageway for supplying the air and oil generally to an automobile or a variety of machineries, equipments and so forth.
2. Description of the Prior Arts
This type of conventional connector for connecting a metallic tube is, as exemplified in FIG. 6, constructed in the following manner. An inner peripheral surface of a cylindrical wall (11') receiving the intrusion of the connecting end of a pipe (T1) and also constituting an enlarged diameter chamber (13) in an as-intruded state is heat-welded (W) by use of a metallic soldering material to the enlarged diameter chamber (13) provided with a stepped portion and communicating with a communication bore (12) formed in an axial core interior of a metallic connector body (11) assuming a desired configuration. Apropos of the resinous tube, as exemplified in FIG. 7, an enlarged diameter chamber (23) provided with the stepped portion communicates with a communication bore (22) formed in the axial core interior of a connector body (21). A pipe (T2) is formed at its end with a collar wall (T2') extending outwards and fitted with a sealing ring member (24) provided behind the collar wall and with a sleeve-like fastening nuts member (25). A cylindrical wall (21'), into which the connecting end of pipe (T2) is incorporated, constitutes enlarged diameter chamber (23) of connector body (21). In this configuration, a threaded surface of a cylindrical wall (21') is screw-fastened through fastening nut member (25) to enlarged diameter chamber (23).
There arise, however, some problems inherent in this type of prior art connector. In the case of the metallic tube, heat-welding (W) by use of the metallic soldering material at high temperatures does not permit the use of the pipe previously electroplated with a typical anti-corrosive film such as zinc or a zinc alloy. The film processing is effected inevitably after the solder-welding has been carried out. For this reason, a variety of bending configurations that pipe (T1) may assume entail the troublesome film processing. This in turn results in a remarkable decline in workability. Besides, during the film processing it is impossible to keep constant both an inter-pole distance and a current density, thereby causing an ununiform thickness of the film. This also causes deterioration in quality. Furthermore, a good deal of processing time is required for securing the least film thickness.
On the occasion of the resinous tube, the screw-processing with respect to cylindrical wall (21') constituting enlarged diameter chamber (23) and fastening nut member (25) is also troublesome. The formation of a relatively large screw-fitting portion generally makes longer cylindrical wall (21') and nut member (25) as well. Where the tube is placed for a long period of time under an oscillating condition, an oft-happened problem is a leakage from the slackened screw-fitting portion.